This invention is based on a multi-cylinder fuel injection pump for internal combustion engines.
A fuel injection pump of this kind is known from U.S. Pat. Nos. 3,677,256; 3,885,895; and 4,222,717. In U.S. Pat. No. 3,885,895 the cylinder sleeves guiding the pump piston are embodied as flanged sleeves, the securing flanges being screwed tightly against the upper end face of the pump housing. This securing arrangement is very laborous and is expensive to fabricate; however, such a pump does permit higher injection pressures than the other prior art patents noted. In some of the prior art pumps, the diameter of the screw-in thread for a screw nipple determines the maximum possible screw-insertion diameter of both the pressure valve body and the cylinder sleeves. As a result, this leaves relatively narrow bearing surfaces for the cylinder sleeves, which in turn limits the axial forces of the screw nipples and thus the maximum allowable pump load or pumping output.
From U.K. Patent 827,678, a further fuel injection pump is known, the pump housing of which comprised two parts, the upper part being of steel and carrying the cylinder sleeves with the pump piston. This steel upper part is very heavy and also quite expensive.